RICHMOND, Va. — Environmental groups and the lead developer of the Atlantic Coast Pipeline were at odds Wednesday over what happens now that a federal appeals court has vacated a key permit for the multistate project.

A spokeswoman for Dominion Energy said construction on the 600-mile natural gas pipeline will go on as scheduled. But lawyers for the environmental groups that sued over a permit dealing with effects on threatened and endangered species say all work must stop.

“We expect the federal agencies to do their jobs” and tell the pipeline to halt construction, attorney D.J. Gerken of the Southern Environmental Law Center said Wednesday. The law centre argued the case on behalf of Defenders of Wildlife, Virginia Wilderness Committee and Sierra Club.

Construction must cease because other federal permits allowing work to proceed are contingent on the U.S. Fish and Wildlife Service approval — called an incidental take statement — vacated by the court, Gerken said.

One federal permit Gerken said should be on hold was issued by the U.S. Army Corps of Engineers.

Tom Walker, chief of the regulatory branch of the Corps’ Norfolk district, said Wednesday that the district is co-ordinating with the Federal Energy Regulatory Commission, the lead agency with oversight, about what’s next.

“I think at this point, it’s everyone trying to find out what the ramifications of this decision are,” he said.

The commission is reviewing the order and will determine “what steps, if any,” are appropriate, spokeswoman Tamara Young-Allen said.

Spokespeople for other affected agencies didn’t respond to inquiries from The Associated Press.

An incidental take statement from the Fish and Wildlife Service usually authorizes a project to harm or kill no more than a limited number of threatened or endangered species. The environmental groups argued, and the court agreed, that the agency failed to set clear limits on the Atlantic Coast Pipeline’s impact.

The brief court order said “the limits set by the agency are so indeterminate that they undermine … enforcement and monitoring function under the Endangered Species Act.”

The court’s order did not directly address construction or other work on the pipeline. The cost of development and construction has grown to between $6 billion and $6.5 billion, and developers aim to have fracked gas flowing south by the fourth quarter of 2019.

Jen Kostyniuk, a spokeswoman for Dominion Energy, wrote in an email that the decision only affects certain activities in certain areas. Trees are being cut down in all three states along the pipeline route, and FERC granted permission last week to commence full construction in parts of West Virginia.

“Although we disagree with the outcome of the court’s decision, and are evaluating our options, we are committed to working with the agency to address the concerns raised by the court’s order,” she wrote.

The pipeline being developed by Dominion, Duke Energy and Southern Company is designed to start in West Virginia and run through Virginia and North Carolina. Developers say it will boost the economy, create jobs and help utilities transition away from coal. Opponents say it will harm the environment, trample on property rights and commit the region to fossil fuels at a time when climate change makes it imperative to invest in renewable energy.